[setup] Lock sphinx to pre 1.7 as mscgen has not been released yet to support it

4 jobs for docker_update in 13 minutes and 25 seconds (queued for 10 seconds)
Status Name Job ID Coverage
  Build
passed build #132216
docker-build

00:13:25

76.0%
failed build #132215
docker-build

00:00:02

failed build #132209
docker-build

00:12:33

76.0%
failed build #132208
docker-build

00:09:51

76.0%